This invention relates to an insulation-piercing connector capable of connecting wires in high density.
Owing to the development of integrated circuit elements and other semiconductor parts, miniaturization of various kinds of electronic appliances has progressed. With such a progression, requirements have been also raised for miniaturization of connectors for use in connection between the electronic appliances.
Therefore, with insulation-piercing connectors, the following modifications have been effected. As shown in FIG. 1a, in an insulating support block 1 of a connector body A are embedded a plurality of contacts, each formed with a pressing slit 2a at a center of its tail 2, and oblique blades 2b on both sides thereof. A plurality of connection wires 3 are pressed into the pressing slits 2a of the tails of contacts by a cover B, so that the blades 2b of each of the contacts 2b are caused to penetrate into a coating 3a of the wire 3 so as to arrive into a core 3b of the wire 3. Thereafter, the connection wires 3 are further pressed into the pressing slits 2a of the tails 2 of the contacts, thereby connecting the wire 3 to the contacts of the connector.
As shown in FIG. 2a, the contact tails 2 are arranged in two rows and the contact tails 2 of each of the rows are arranged with minimum distances so that the connection wires 3 are able to be inserted into the pressing slits 2a without difficulty. Moreover, the pressing slit 2a of each contact tail 2B in the second row is arranged at a center between the pressing slits 2a of adjacent two contact tails 2A in the first row so that the contact tails 2A and 2B are arranged in a so-called "staggered arrangement" as shown in FIGS. 2a and 2b. It has been actually effected to make the length of the support block 1 as short as possible by making diameters D of the connection wires 3 and widths R of the contact tails 2 as small as possible.
However, there is a limitation for the reduction in diameter of wires and width of contact tails because of problems caused from electric current to be supplied and mechanical strength of the contact tails. For example, the contact tail is required to have mechanical strength to a certain extent for preventing any faulty connection of wires resulting from deformations of the oblique blades 2b in pressing the wires into the pressing slits 2a of the contact tails. It is actually difficult to make the diameter D of wires less than 0.3 mm and the width W of the contact tails less than 0.75 mm. Therefore, any particular idea is required for accomplishing further miniaturization of connectors.